This invention relates generally to an improved label for food and drink containers made using an injection molding process. Specifically, this invention relates to a label ledge which supports a label that is applied to the product packaging during the injection molding process which results in a stronger, more attractive container than those made using in mold labeling.
Many plastic products are made using either injection or blow mold technology. Products that are made by injection molding are typically made using either a low melt resin or a high melt resin. When a lightweight or thin walled container is desired, it is generally more cost effective to make it from a high melt resin. This is because the high melt resin is more fluid at its processing temperature, and can more easily flow into the mold than can the low melt resin at its processing temperature. This quality permits the manufacturer to produce the products much more quickly using a high melt resin because the cycle time can be reduced.
Often it is desirable to place labels or designs on molded products. These labels or designs may either be applied to the product during the manufacturing of the product by using an in mold label, or afterwards using a label which is glued, printed, or otherwise applied to the finished product. It is generally more desirable to use an in mold label when creating commercial containers, because the label then becomes an integral part of the container. In mold labels generally create a more attractive product than labels which are glued or otherwise applied to the container after it has been manufactured. In addition to the initial appearance, using an in mold label also increases the commercial value of the container by creating a product that will remain attractive and visible after its direct use as a delivery container. Labels that are glued or otherwise applied to the container after manufacturing often peel or wash off. A label applied in mold will remain with the container as long as the container exists, with essentially the same appearance as the day the container was manufactured, thus creating a relatively permanent advertisement. This is particularly true when a label is applied to food product containers, which are often reused for food storage or consumption after the initial contents have been consumed.
Conventional or lenticular labels used during the injection molding process commonly obtain a latent fracture along the seam line, or other straight edges, when a label is applied in mold. A latent fracture can easily be turned into a full fracture by applying pressure on opposite sides of the container to which a traditional label has been applied. This is undesirable in a product subjected to repeated squeezing, such as drinking cups and container tops. Moreover, when these containers are subjected to extreme temperatures, such as when they contain ice cream, the extreme temperatures often cause a full fracture to develop along the latent fracture line.
In order to avoid such fractures, manufacturers typically use low melt resin to create containers to which labels are applied in mold. The sturdier container, which results from using the low melt resin, is less prone to fracture. However, using the low melt resin increases the cost of each container because of the increased processing time. In addition, the resulting containers are often heavier or have thicker walls than necessary for the product that the container is designed to hold.
In addition, manufacturers must typically keep large stocks of resin on hand for use in the molding process. Some manufacturers use high melt resin for the bulk of their products, but must also keep low melt resin available to produce in mold labeled products which cannot be made out of high melt resin, solely because the of the latent fractures created by the traditional in mold labels. By using a label which can be applied in mold to a high melt resin container, manufacturers may be able to avoid maintaining this additional stock of low melt resin.
Often the injection molding process drags ink from the edge cuts of the in mold label into the resin used to form the container, causing undesirable streaks in the resulting container. These streaks appear in the stacking ring and body of a container, which is generally unlabeled and downstream from the injection site. Although the resulting ink streaks are harmless, they are commercially unacceptable. As a result, a portion of each batch of containers must be discarded because their appearance is unacceptable. This streaking occurs when both low melt and high melt resin are used, and cannot be overcome by selection of an appropriate resin type.
Many containers formed via the injection molding process have radiused corners. For example, plastic cups commonly have a body that extends from a base. In some cases the body extends radially outwardly from the base. Problems arise when the corners or radiused portions of the container are adjacent the area where the in mold label is to be placed.
In an in mold labeling injection molding process, the mold has radii formed at various portions to define the cup or container. The label is placed along a cavity wall within the mold at the desired location. When the resin is injected into the mold, the resin flow of plastic often pushes the label out of the desired location, as opposed to pinning the label along the cavity wall of the mold. The flow of resin displaces the label away from the cavity wall and flows around both sides of the label, causing scrap. This leads to the wasting of large amounts of molding material, which correlate to increased manufacturing costs. Furthermore, the labels are not currently placed on elevated planes of containers. The labels are typically placed on the container, but not on the bottom of the container.
Finally, lids are often placed onto these cups and containers. Labels may be placed onto the lids to preserve the products residing therein. The labels may be decorative and positioned along the side panel of the lid, known as skirting, as well as on the top, or pan area, of the lid. However, the attempts to place labels on the container lids encounter the same challenges as seen with the labels placed around the container body: The lids have corners or radiused portions adjacent the area where the in mold label is to be placed.
Thus, a need exists for a label that can be applied during the injection molding process that does not permit displacement of a label during the flow of resin through the mold. Further, there is a desire to place labels on in mold container on an elevated plane. Finally, there is a desire to apply labels to containers as well as container lids during the injection molding process with an aesthetically pleasing result.